relatedly, I used to use a 4x bay USB3 caddy for some disks.. It was OK, but didn't expose the raw disks and the controller was pretty fucky swallowing things like SMART.
Are you running something like Unraid or TrueNAS, or are you just running a 'regular' Linux distro?
Ubuntu + ZFS. I don't see the appeal of running a non-mainline distribution. All I did was set it up so ZFS sends me emails and a crontab to run a ZFS resilver weekly.
Ah, they might have killed that option in newer kernels. Vaguely remember something about it being a temporary fix, I guess its time has come.